Nicotiana attenuata MPK4 suppresses a novel jasmonic acid (JA) signaling-independent defense pathway against the specialist insect Manduca sexta, but is not required for the resistance to the generalist Spodoptera littoralis.
Nicotiana attenuata MPK4 suppresses a novel jasmonic acid (JA) signaling-independent defense pathway against the specialist insect Manduca sexta, but is not required for the resistance to the generalist Spodoptera littoralis.
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DOI：
10.1111/nph.12312
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发表时间：
2013-08
期刊：
影响因子：
--
通讯作者：
Wu J
中科院分区：
文献类型：
--
作者：
Hettenhausen C;Baldwin IT;Wu J
植物是如何根据不同昆虫的攻击来调整它们的防御反应的，这在很大程度上仍然未知。本研究研究了丝裂原活化蛋白激酶（MAPK） MPK4在野生烟对两种食草动物——专生性Manduca sexta和通吃性Spodoptera littoralis的抗性中的作用。在MPK4基因沉默中稳定转化的薄叶松（N. attenuata）植株（irMPK4）被培育出来，并被鉴定为具有防御食草动物的重要性状。在irMPK4植株中，与野生型植株相比，只有sexta的口腔分泌物（OS）能诱导茉莉酸（JA）水平升高，而littoralis的口腔分泌物（OS）或机械损伤则不能。此外，沉默MPK4可以不依赖COI1 （CORONATINE INSENSITIVE 1）介导的JA信号传导，以一种不依赖于COI1介导的方式，高度增加玉米对m.s sexta的抗性。非靶向代谢组学筛选鉴定了几种新的mpk4依赖性推定防御化合物。相比之下，MPK4的沉默不影响一般昆虫的生长，我们认为这是由于脂肪酸-氨基酸偶联物（FACs）水平非常低。因此，MPK4可能是一个关键的信号元件，使植物能够针对不同的攻击者量身定制防御反应。
How plants tailor their defense responses to attack from different insects remains largely unknown. Here we studied the role of a mitogen-activated protein kinase (MAPK), MPK4, in the resistance of a wild tobacco Nicotiana attenuata to two herbivores, the specialist Manduca sexta and the generalist Spodoptera littoralis. Stably transformed N. attenuata plants silenced in MPK4 (irMPK4) were generated and characterized for traits important for defense against herbivores. Only the oral secretions (OS) from M. sexta, but not the OS from S. littoralis or mechanical wounding, induced elevated levels of jasmonic acid (JA) in irMPK4 plants compared to the wild-type plants. Moreover, silencing MPK4 highly increased the resistance of N. attenuata to M. sexta in a fashion that was independent of COI1 (CORONATINE INSENSITIVE 1)-mediated JA signaling. Untargeted metabolomic screening identified several new MPK4-dependent putative defensive compounds against M. sexta. In contrast, silencing MPK4 did not affect the growth of the generalist insect S. littoralis, and we propose that this was due to the very low levels of fatty acid-amino acid conjugates (FACs) in S. littoralis OS. Thus, MPK4 is likely to be a key signaling element that enables plants to tailor defense responses to different attackers.